A DPDPE-induced enhancement of inward rectifier potassium current via opioid receptor in neuroblastoma x glioma NG108-15 cells

The effect of a delta-selective opioid agonist, DPDPE([D-Pen(2,5)]-enkephal in), on the inward rectifier potassium current (I-KIR) of NG108-15 cell was studied by whole cell voltage-clamp technique. It was found that mu M DPDP E increased the amplitude and delayed the activation and inactivation of I- KIR rapidly and reversibly. These effects could be reversed by naloxone, bu t were still obtained in pertussis toxin (PTX) preincubated cells or when u sing GDP-beta s (guanosine 5'-o-[2-thio] diphoaphate) containing electrodes to block the G-protein coupled events. The above results suggest that DPDP E-induced change of I-KIR is mediated by delta-opioid receptor but does not involve C-proteins. (C) 2000 Elsevier Science Ireland Ltd. All rights rese rved.